Magnetic and electric properties of triangular lattice antiferromagnets Ba3ATa2O9 (A= Ni and Co)

Lee, Minseong; Choi, Eun Sang; Ma, Jie; Sinclair, R.; Zhou, H. D.

doi:10.1016/j.materresbull.2016.12.039

Cited by 10 publications

(8 citation statements)

References 27 publications

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“…The table contains also the data available in the literature for comparison. Our findings regarding lattice parameters (a and c) agree to within 2% with those of experiments 14,45,46,[48][49][50][51][52] and are in reasonable accord with those computed using other approaches. 29 This constitutes the first proof of the reliability of the current calculations.…”

Section: Resultssupporting

confidence: 90%

Probable thermoelectric materials for promising candidate of optoelectronics for Ba‐based complex perovskite compounds

Berri

Bouarissa

2021

Intl J of Energy Research

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Structural parameters, electronic band structure, optical spectra, and thermoelectric properties of trigonal Ba 3 B(Nb, Ta) 2 O 9 (B═Sr, Mg, Ca, Hg, Zn, Fe, Ni, Mn, Co, and Ca) compound materials are investigated. The computations are performed using density-functional calculations within the generalized gradient approximation. The calculated a and c parameters agree with those of the experiment to within 2%. The Ba 3 B(Nb, Ta) 2 O 9 (B=Sr,Mg,Ca, Hg, Zn, Fe, Ni, Mn, Co, and Ca) materials are found to be semiconductors with a band-gap energy varying from 0.82 to 3.17 eV. A metallic character is observed in Ba 3 B(Nb, Ta) 2 O 9 (B═Ni, Mn, and Co) compounds indicating the presence of conductivity features. A small carrier effective mass indicates the increase of the electron mobility leading to a high n-type conductivity. The p states dominate the lower valence band region. The optical spectra show an anisotropic character between x and z directions. The excitonic effects tend to increase the strength of the oscillator at M 0 and M points. The effect is reduced when increasing the photon energy, indicating that the Ba 3 BB 2 'O 9 compound can be used for devices such as Bragg's reflectors, and optical and optoelectronic devices. The calculations were performed using the BoltzTrap code, which depends on the semi-classical Boltzmann transport equation. The Seebeck coefficient, electrical conductivity, thermal conductivity, power factor, and the figure of merit for Ba 3 (Fe, Sr, Hg, Zn)B 0 2 O 9 are calculated. At higher temperatures, the mobility increases by reducing the electrical conductivity. Ba 3 (Fe, Sr, Hg, Zn) B 2 ' O 9 shows a considerable thermoelectric performance accompanied by a sign point figure of merit larger than many full perovskites reported till date. K E Y W O R D S ab initio calculations, Ba 3 BB 0 2 O 9 , electronic structure, optical properties, thermoelectric properties 1 | INTRODUCTION Complex perovskites Ba 3 BB 0 2 O 9 are composed of at least two different B cations that can take a variety of valences. 1,2The difference in the nature of the B cations leads to an ordering in the B site. Some of these complex oxides exhibit NaCl-type B-site ordering with cubic symmetry (SG Number 225), often referred to as 1:1 type, whereas

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Section: Resultssupporting

confidence: 90%

Probable thermoelectric materials for promising candidate of optoelectronics for Ba‐based complex perovskite compounds

Berri

Bouarissa

2021

Intl J of Energy Research

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“…Best material prototypes of Co-based triangular antiferromagnets are found among hexagonal perovskites of the 6H-Ba 3 CoX 2 O 9 family with X = Sb [65][66][67], Nb [68,69], and Ta [70,71] (Fig. 3a).…”

Section: B Hexagonal Perovskites and Magnetic Excitationsmentioning

confidence: 99%

Spin liquids in geometrically perfect triangular antiferromagnets

Gegenwart

Tsirlin

2020

J. Phys.: Condens. Matter

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The cradle of quantum spin liquids, triangular antiferromagnets show strong proclivity to magnetic order and require deliberate tuning to stabilize a spin-liquid state. In this brief review, we juxtapose recent theoretical developments that trace the parameter regime of the spin-liquid phase, with experimental results for Co-based and Yb-based triangular antiferromagnets. Unconventional spin dynamics arising from both ordered and disordered ground states is discussed, and the notion of a geometrically perfect triangular system is scrutinized to demonstrate non-trivial imperfections that may assist magnetic frustration in stabilizing dynamic spin states with peculiar excitations.

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“…Niobium or tantalum oxyfluoride anions [MO x F y ] n − (M = Nb, Ta) have been widely used to design and explore novel functional materials due to their rich chemical structure diversity, particularly for nonlinear optical materials attributed to the second-order Jahn–Teller distortion of Nb 5+ /Ta 5+ with d 0 electron configuration. As well, niobium or tantalum oxyfluoride anions [MO x F y ] n − (M = Nb, Ta) have been acted as basic building units for constructing low dimensional magnetic systems, such as triangular lattice systems of A 3 M’Nb 2 O 9 (A = Ca, Sr, Ba; M’ = Co, Ni, Mn), − Ba 8 CoNb 6 O 24 , and Ba 3 M”Ta 2 O 9 (M” = Co, Ni, Mn). , Meanwhile, organic molecule pyrazine (pyz) are also used to design and form low-dimensional magnets, including CuF 2 (pyz)(H 2 O) 2 , [Cu 2 F(HF)(HF 2 )(pyrazine) 4 ](SbF 6 ) 2 , CoF 2 (pyz)(H 2 O) 2 and so on.…”

Section: Introductionmentioning

confidence: 99%

“…As well, niobium or tantalum oxyfluoride anions [MO x F y ] n− (M = Nb, Ta) have been acted as basic building units for constructing low dimensional magnetic systems, such as triangular lattice systems of A 3 M'Nb 2 O 9 (A = Ca, Sr, Ba; M' = Co, Ni, Mn), 28−32 Ba 8 CoNb 6 O 24 , 33 and Ba 3 M"Ta 2 O 9 (M" = Co, Ni, Mn). 34,35 Meanwhile, organic molecule pyrazine (pyz) are also used to design and form low-dimensional magnets, including CuF 2 (pyz)(H 2 O) 2 , 36 [Cu 2 F(HF)(HF 2 )(pyrazine) 4 ](SbF 6 ) 2 , 37 CoF 2 (pyz)(H 2 O) 2 38 and so on. Combining multiple anions is a promising way to design and achieve novel compounds with a great diversity of functional properties.…”

Section: ■ Introductionmentioning

confidence: 99%

CoMOF₅(pyrazine)(H₂O)₂ (M = Nb, Ta): Two-Layered Cobalt Oxyfluoride Antiferromagnets with Spin Flop Transitions

et al. 2021

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Two cobalt oxyfluoride antiferromagnets CoMOF5(pyz)(H2O)2 (M = Nb 1, Ta 2; pyz = pyrazine) have been synthesized via conventional hydrothermal methods and characterized by thermogravimetric (TGA) analysis, FTIR spectroscopy, electron spin resonance (ESR), magnetic susceptibility, and magnetization measurements at both static low field and pulsed high field. The single-crystal X-ray diffraction indicates both compounds 1 and 2 are isostructural and crystallize in the monoclinic space group C2/m with a two-dimensional Co2+ triangular lattice in the ab plane, separated by the nonmagnetic MOF5 (M = Nb 1, Ta 2) octahedra along the c-axis with large intertriangular-lattice Co···Co distance. Because of low dimensionality together with frustrated triangular lattice, compounds 1 and 2 exhibit no long-range antiferromagnetic order until ∼3.7 K. Moreover, a spin flop transition is observed in the magnetization curves at 2 K for both compounds, which is further confirmed by ESR spectra. In addition, the ESR spectra suggest the presence of a zero-field spin gap in both compounds. The high field magnetization measured at 2 K saturates at ∼7 T with M s = 1.55 μB for 1 and 1.71 μB for 2, respectively, after subtracting the Van Vleck paramagnetic contribution, which is usually observed for Co2+ ions with pseudospin spin of 1/2 at low temperature. Powder-averaged magnetic anisotropy of g = 3.10 for 1 (3.42 for 2) and magnetic superexchange interaction J/k B = −3.2 K for 1 (−3.6 K for 2) are obtained.

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Magnetic and electric properties of triangular lattice antiferromagnets Ba3ATa2O9 (A= Ni and Co)

Cited by 10 publications

References 27 publications

Probable thermoelectric materials for promising candidate of optoelectronics for Ba‐based complex perovskite compounds

Probable thermoelectric materials for promising candidate of optoelectronics for Ba‐based complex perovskite compounds

Spin liquids in geometrically perfect triangular antiferromagnets

CoMOF₅(pyrazine)(H₂O)₂ (M = Nb, Ta): Two-Layered Cobalt Oxyfluoride Antiferromagnets with Spin Flop Transitions

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Magnetic and electric properties of triangular lattice antiferromagnets Ba3ATa2O9 (A= Ni and Co)

Cited by 10 publications

References 27 publications

Probable thermoelectric materials for promising candidate of optoelectronics for Ba‐based complex perovskite compounds

Probable thermoelectric materials for promising candidate of optoelectronics for Ba‐based complex perovskite compounds

Spin liquids in geometrically perfect triangular antiferromagnets

CoMOF5(pyrazine)(H2O)2 (M = Nb, Ta): Two-Layered Cobalt Oxyfluoride Antiferromagnets with Spin Flop Transitions

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CoMOF₅(pyrazine)(H₂O)₂ (M = Nb, Ta): Two-Layered Cobalt Oxyfluoride Antiferromagnets with Spin Flop Transitions